KR101510931B1 - Method for emergency stopping vinyl chloride based polymers by suspension polymerization and apparatus used therein - Google Patents

Abstract

The present invention relates to a process for producing a vinyl chloride polymer by suspension polymerization, in which polymerization progress is impossible due to electrostatic or machine failure, or in case of occurrence of an abnormal reaction, heat release is not properly carried out by an exothermic reaction, The present invention relates to a method and an apparatus capable of stopping the polymerization when the reactor (2) can be exploded. The polymerization stopper solution is prepared and stored in a water tank tank (1) equipped with a stirrer so as to prepare a polymerization terminator, To a method of effectively stopping polymerization by transferring a reactant through a line provided at the bottom of the reactor (2) when a situation occurs, and a device used therefor.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an emergency stopping method of a vinyl chloride polymer by suspension polymerization,

The present invention relates to an emergency stopping method of a vinyl chloride polymer by suspension polymerization and an apparatus for use in the reaction of the vinyl chloride polymer by suspension polymerization, wherein heat release is not properly performed due to an exothermic reaction at the occurrence of static electricity and an abnormal reaction, Wherein the reaction of the vinyl chloride polymer is stopped by transferring the reactant to the water tank tank (1) connected to the reactor (2) in order to prevent the danger of explosion of the vinyl chloride polymer (2) To an emergency stop method during the reaction and a device used therefor.

The vinyl chloride polymer refers to an interpolymer obtained by polymerizing a mixture of vinyl chloride or a monomer copolymerizable with vinyl chloride. The vinyl chloride polymer is one of general-purpose plastics and has been used in various fields because of its low cost, excellent processability and simple polymerization process. The polymerization of the vinyl chloride polymer is mainly carried out by suspension polymerization or emulsion polymerization. Emulsion polymerization is a polymerization method for producing particles of about 0.1 to 2 탆 using water, an emulsifier, a vinyl chloride monomer, and an initiator. The vinyl chloride polymer produced by the emulsion polymerization method has good flowability during processing and excellent foaming property and is widely used as a flooring material. The suspension polymerization method is a polymerization method for producing particles of about 150 μm using water, a suspension stabilizer, a vinyl chloride monomer, and an initiator, and is excellent in electrical insulation and chemical resistance, and is used for various purposes such as wire covering, pipes, and window frames.

The skin layer of the remains is stabilized by the suspension stabilizer at the initial stage of the polymerization in the process of forming the vinyl chloride polymer produced by the suspension polymerization method and the radicals generated by the decomposition of the initiator in the interior of the residue stabilize the vinyl chloride polymer by 0.5 to 2 Primary particles of about 탆 are formed and primary particles are aggregated to form a grain of about 50 탆. These grains are aggregated to finally form particles of a vinyl chloride polymer having a size of about 150 mu m.

The polymerization process of the vinyl chloride monomer is an exothermic reaction in which a cold water is flowed through a jacket 4 installed on the wall of the reactor 2 and a baffle installed inside the reactor 2 to control the heat generated during the reaction, have. Due to the development of vinyl chloride polymer production technology, the reflux condenser (3) is reduced in size because the surface area that can be removed by the baffle installed in the wall of the reactor (2) and inside is reduced as compared with the increased use amount of the vinyl chloride monomer And a method of effectively removing heat from the vaporized vinyl chloride monomer by re-condensing the vaporized vinyl monomer. However, since the amount of heat generated by using the jacket 4, the baffle, and the reflux condenser 3 is limited, the pressure in the reactor 2 increases due to the increase of the temperature inside the reactor 2, There is a limit to prevent the danger.

As a method for preventing this, European Patent No. 0064628 discloses a method in which a polymerization terminator line is connected to the lower portion of a reactor to introduce a polymerization terminator using an inert gas while the plate installed in the line is broken due to an increased pressure when an emergency occurs, . However, even if the polymerization terminator is added from the lower part of the reactor, the polymerization terminator is difficult to effectively use because it is not properly stirred.

Japanese Unexamined Patent Application, First Publication No. Hei 8-134106 discloses that a polymerization stopper inlet is provided at a position where an impeller is installed for effective stirring so that stirring can be effectively performed when an emergency occurs. However, when a situation such as a power failure occurs, the polymerization process of the vinyl chloride monomer can not be properly stopped because stirring can not be performed.

It is an object of the present invention to provide a process for producing a vinyl chloride polymer in which a reactor 2 is provided to prevent the risk that the reactor 2 may explode when the reaction temperature and the pressure increase due to a problem caused by a power failure or a machine failure, ) And a water tank tank (1) containing a polymerization terminator and water through a line connected to the bottom of the tank (1) to prevent dangerous situations in an emergency situation.

The above object of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present invention includes a water tank tank 1 connected to a lower end of a reactor 2 through a valve separately from a blowdown line 6, and the water tank tank 1 is connected to the reactor 2 ) Containing a polymerization terminator solution having a volume of 150% or more of the volume, and the valve is manually operated at the time of an emergency stop.

The present invention also relates to a process for producing a vinyl chloride polymer by using the above-described emergency stopping apparatus for a vinyl chloride polymer and a reactor (2) in which a reaction product containing a vinyl chloride monomer, a suspension stabilizer and a polymerization initiator is subjected to suspension polymerization, ) Is opened to move the reactant downward according to the difference in internal pressure and height so that the reactant is transferred to the water tank tank (1).

According to the present invention, there is an effect that it is possible to prevent the risk that the reactor is exploded due to a failure of heat removal due to an exothermic reaction when a power failure or an abnormal reaction occurs during the polymerization of the vinyl chloride polymer.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of an emergency stopping apparatus for a vinyl chloride polymer used in the present invention. FIG.

In order to achieve the above object, the present invention provides an emergency stop apparatus for a vinyl chloride polymer, which comprises a water tank tank (1) connected to the lower end of a polymerization reactor (2).

The present invention also relates to a process for producing a vinyl chloride polymer, which comprises using the above-described emergency stopping device for a vinyl chloride polymer and carrying out suspension polymerization of a reaction product containing a vinyl chloride monomer, a suspension stabilizer and a polymerization initiator in the reactor (2) The valve provided on the line connecting the water tank 1 is manually opened so that the reactants in the reactor 2 are moved downward according to the difference in internal pressure and height to be transferred to the water tank 1. [ Thereby providing an emergency stopping method of the vinyl polymer.

Hereinafter, the present invention will be described in detail.

In the case of a situation in which polymerization can not proceed normally due to power failure or machine failure during the production of vinyl chloride polymer which is subjected to suspension polymerization using vinyl chloride monomer, suspension stabilizer and initiator as raw materials, The temperature and pressure inside the reactor 2 due to the exothermic reaction are increased. In order to prevent such a situation, in the present invention, in order to prevent the reactant from flowing into the lower part of the reactor (2) by a free fall due to a pressure difference and a height difference A line capable of being transported is provided to connect the solution containing the polymerization terminator to the tank tank 1 prepared in advance. Accordingly, when the line connected to the water tank 1 is opened, the reactant moves downward according to the difference in internal pressure and height, and the reactant is transferred to the water tank 1. A line connected to the water tank 1 may be additionally installed on the blow down line at the bottom of the reactor 2 so that the water can be selectively used depending on the situation.

Since the outer wall of the water tank tank 1 is maintained in a state of being shielded from the outside and the water tank tank 1 is opened for discharging gas generated therein, (1) Install a gas discharge line on the top to prevent the internal pressure from rising.

Further, the water tank tank 1 may be provided with a stirrer 5 so as to prepare a polymerization terminator solution. The volume of the water tank tank 1 may be 150% or more of the volume of the reactor 2, specifically, 180% to 220%, but is not particularly limited as long as it can contain both the polymerization terminator and the reactant.

The present invention is characterized in that the reactor 2 and the water tank tank 1 are connected to each other during the suspension polymerization of a reaction product containing a vinyl chloride monomer, a suspension stabilizer and a polymerization initiator in the reactor 2, And the reaction product is moved downward according to the difference in internal pressure and height, so that the reactant is transferred to the water tank tank (1). Whether or not the reaction is terminated is determined by observing the change in the temperature inside the water tank 1 for a predetermined period of time and checking whether the internal temperature is raised. The time point at which the polymerization can be stopped by being transferred to the water tank 1 can be performed throughout the polymerization time.

The present invention relates to a method for producing a vinyl chloride polymer produced by suspension polymerization using an initiator, water, a suspension stabilizer, a vinyl chloride monomer or a copolymerizable monomer, but there is no limitation in the production method of the vinyl chloride polymer.

In this regard, the water tank tank 1 contains a polymerization terminator solution in its interior and may contain an amount of 0.1 to 30 parts by weight, specifically 1 to 15 parts by weight, based on 100 parts by weight of water .

The vinyl chloride polymer includes not only a resin made of a pure vinyl chloride monomer but also a mixture of a vinyl monomer mainly composed of a vinyl chloride monomer and a vinyl monomer copolymerizable therewith (the content of the vinyl chloride monomer in the resin composition is not less than 50% by weight) do.

Examples of the vinyl monomer copolymerizable with the vinyl chloride monomer include olefin compounds such as ethylene and propylene; Vinyl esters such as vinyl acetate and vinyl propionate; unsaturated nitriles such as acrylonitrile; vinyl alkyl ethers such as vinyl methyl ether and vinyl ethyl ether; Unsaturated fatty acids such as acrylic acid, methacrylic acid, itaconic acid and maleic acid, and anhydrides of these fatty acids, can be used alone or in admixture of two or more kinds of copolymerizable monomers of vinyl chloride monomers.

Initiators used in the vinyl chloride polymerization include diacyl peroxides such as dicumyl peroxide, dipentyl peroxide, di-3,5,5-trimethylhexanoyl peroxide and diaryl peroxide, diisopropyl oxycarbonate, Peroxydicarbonates such as di-sec-butylperoxydicarbonate and di-2-ethylhexyl peroxydicarbonate; butyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, t-amyl peroxyne teecanoate, cumyl peroxyneodecanoate, cumyl peroxyneoheptanoate, Peroxy esters such as 3,3-tetramethyl butyl peroxyneodecanoate; Azo compounds such as azobis-2,4-dimethylvaleronitrile; Potassium persulfate, ammonium persulfate and the like, and they may be used alone or in combination of two or more.

Examples of the antioxidant that can be used before the reaction is stopped in the present invention include triethylene glycol-bis- [3- (3-t-butyl- Methyl-4-hydroxyphenyl) propionate], hydroquinone, p-methoxyphenol, t-butylhydroxyanisole, n-octadecyl-3- (3-methyl-6-t-butylphenol), t-butylcatechol, 4-tert-butyldiphenylborate Phenol compounds such as 4-thiobis (6-t-butyl-m-cresol) and tocopherol, and N, N-diphenyl-p-phenylenediamine and 4,4-bis (dimethylbenzyl) Amine compounds, dodecyl mercaptans, sulfur compounds such as 1,2-diphenyl-2-thiol, triphenyl phosphite, diphenyldecyl phosphite, phenyl isodecyl phosphite, tri (nonylphenyl) phosphite, Our Triti A phosphoric acid-based antioxidants such as phosphites may be mixed alone or in combination.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Changes and modifications may fall within the scope of the appended claims.

To facilitate understanding of the present invention, a polymerization method of a vinyl chloride polymer is shown as a production example, but the production method for carrying out the present invention is not limited. Examples for terminating the polymerization in the middle of the reaction are also shown below.

[Example]

Manufacturing example

, 130 parts by weight of polymerized water, 0.05 part by weight of polyvinyl alcohol having a degree of hydration of 88%, a polyvinyl alcohol having a degree of hydration of 72%, and a polyvinyl alcohol having a degree of hydration of 72% were added to a stainless polymerization reactor (2) having an internal volume of 1 m ³ equipped with a reflux condenser (3) , 0.01 part by weight of polyvinyl alcohol having a moisture content of 55%, 0.01 part by weight of hydroxypropylmethylcellulose, 0.07 part by weight of t-butylperoxyneodecanoate (BND), 0.5 part by weight of? -Cumylperoxineodecano (CND) was added thereto, and the inside was degassed with a vacuum pump while stirring, and 100 parts by weight of a vinyl chloride monomer was added thereto. In addition to the polymerization initiation, the valve of the reflux condenser (3) was opened to eliminate the pressure change.

The temperature of the polymerization reactor (2) was maintained at 57 캜 during the prepolymerization process. Then, the polymerization was stopped when the pressure in the polymerization reactor (2) was changed to 1.0 kg / cm ² .

Then, 0.05 part by weight of triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] was added as an antioxidant to recover unreacted monomers, And recovered in the polymerization reactor (2).

Example  One

After 20 minutes of polymerization time, the reactor was stopped and the stirrer was stopped and the temperature and pressure inside the reactor (2) were checked to simulate the situation similar to the emergency state. To terminate the reaction, the reactor (2) the interior volume by opening a line to the lower bath tank 1 a water bath tank (1) with a solution prepared by adding water to 100 parts by weight of a polymerization terminator 10 parts by weight of the 2m ³ .

Example  2

The procedure of Example 1 was repeated except that the stirrer was stopped after 100 minutes of polymerization time in Example 1.

Example  3

The procedure of Example 1 was repeated except that the stirrer was stopped after 170 minutes of polymerization time in Example 1.

The stop time of the stirrer shown in Examples 1 to 3 was set to 20 minutes, 100 minutes, and 170 minutes, respectively, in order to observe the effect of stopping the polymerization depending on the state of polymerization, . In order to similarly reproduce an emergency situation such as a power failure, the operation of the jacket 4 and the reflux condenser 3 of the reactor 2 was stopped at the time when the stirrer stopped.

In Examples 1 and 2 in which the stirrer and the regenerator were stopped in the middle of the middle, about three minutes after the stop of the operation of the stirrer and the heat generator, the valve in the line connected to the lower portion of the reactor 2 was opened to supply neutralized water and vinyl chloride monomer The substances which were undergoing polymerization were transferred to the tank 1. This is based on the time that the valve can be opened at the time of an emergency such as a power failure. Until the valve was opened, the temperature inside the reactor 2 rose by 2 ° C and the pressure rose by 0.7 kg / cm ² . However, the range of the increased temperature and pressure can be determined by changing the temperature and pressure change range within the reactor 2 because the cooling water staying in the jacket 4 and the reflux condenser 3 used may vary in temperature due to seasonal variations Can be changed. After transferring to the tank tank 1 and checking the internal temperature and pressure state of the tank tank 1 even after 30 minutes, it was confirmed that the reaction was safely terminated due to no further rise in temperature and pressure.

In Example 3 in which the operation was stopped at the end of the reaction, the operation of the stirrer and the heat generator was stopped and the temperature rose by 4 ° C until the valve connected to the water tank 1 was opened. The pressure rose by 1.5 kg / cm ² . The reaction rate increased due to the gel effect at the end of the reaction due to the polymerization characteristics of the exothermic vinyl chloride monomer. As a result of checking temperature and pressure changes after transferring to the tank (1), it was confirmed that the reaction was safely terminated due to no further rise in temperature and pressure. The materials transferred to the tank tank (1) were treated in the same manner as the general polymerization process such as the recovery process of the vinyl chloride monomer.

1: tank tank 2: reactor
3: Reflux condenser 4: Jacket
5: tank tank stirrer 6: blow down line
7: vinyl chloride monomer recovery line

Claims (11)

And a water tank tank (1) connected to the lower end of the reactor (2) through a valve separately from the blowdown line (6)
The water tank tank (1) is a tank containing a polymerization terminating agent solution having a volume of 150% or more of the volume of the reactor (2)
Characterized in that the valve is manually operated during an emergency stop. The method according to claim 1,
Wherein the water tank tank (1) is provided with an agitator (5). delete The method according to claim 1,
Characterized in that the outer wall of the water tank (1) is maintained in a state of being disconnected from the outside, and a gas discharge line is provided on the upper part thereof. The method according to claim 1,
Characterized in that the volume of the water tank tank (1) is 180 to 220% of the volume of the reactor (2). The method according to claim 1,
The valve provided on the line connecting the reactor 2 and the water tank 1 is manually opened so that the reactants in the reactor 2 fall down freely according to the difference in internal pressure and height, Wherein the polyvinyl chloride polymer emulsion is transferred. An emergency stopping apparatus for a vinyl chloride polymer according to claim 1, wherein during the suspension polymerization of a reaction product containing a vinyl chloride monomer, a suspension stabilizer and a polymerization initiator in the reactor (2) during an emergency stop, the reactor (2) (1) is manually opened to move the reactants in the reactor (2) downward according to the difference in internal pressure and height, and is transferred to the water tank tank (1) . 8. The method of claim 7,
Characterized in that the water tank tank (1) contains a polymerization terminator solution in its interior and comprises an amount of 0.1 to 30 parts by weight per 100 parts by weight of water. 8. The method of claim 7,
Wherein the end point of the emergency stop reaction is a time point at which no temperature rise occurs in the water tank tank (1). 8. The method of claim 7,
The vinyl chloride monomer is a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and a vinyl monomer copolymerizable therewith, and the copolymerizable vinyl monomer is selected from the group consisting of an olefin compound, a vinyl ester, an unsaturated nitrile, a vinyl alkyl ether, And at least one selected from the group consisting of anhydrides of these fatty acids. 8. The method of claim 7,
And the time point at which the polymerization can be stopped by being transferred to the water tank (1) can be performed throughout the polymerization time.

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